Composite material with improved properties

ABSTRACT

A polyolefin resin composition comprising a polyolefin modified with an unsaturated carboxylic acid, at least one member selected from the group consisting of polyepoxides, polyisocyanates, and polyamines, and a reinforcement.

CROSS REFERENCE TO THE RELATED APPLICATION

This is a continuation-in-part application of application Ser. No. 450,378 filed on Dec. 16, 1982, now pending.

FIELD OF THE INVENTION

The present invention relates to a composite material with improved properties which can provide a molded product having excellent various properties.

BACKGROUND OF THE INVENTION

Thermoplastic composite materials have excellent mechanical and electrical properties, and investigations for use as industrial materials have recently been developed rapidly. Of polymers constituting the composite materials, polyolefins such as polyethylene, polypropylene, and so forth have characteristics such as small specific gravity, good moldability and processability, excellent chemical resistance, and so forth, and applications of the thermoplastic composite materials comprising polyolefins as a matrix will now increase.

However, since polyolefins constituting the thermoplastic composite materials are nonpolar polymers, they do not have a satisfactory affinity for glass fibers, carbon fibers, carbon black, mica, talc, alumina fibers, silicon carbide fibers, aromatic polyamide fibers, and so forth which are used as a reinforcement. Therefore, a thermoplastic composite material having a further improved reinforcing effect has been demanded.

Many investigations have been made to develop a thermoplastic composite material satisfying the above requirement.

For example, Japanese Patent Application (OPI) No. 74649/1977 (the term "OPI" as used herein refers to a "published unexamined Japanese patent application") describes a material prepared by adding 0.2 to 2 wt% of polyacrylic acid to a composite material composed of 50 to 95 parts by weight of a polyolefin and 5 to 50 parts by weight of an inorganic filler. However, this composite material cannot be said to possess sufficiently improved properties because the affinity of the matrix polymer for the filler has not yet been improved. Japanese Patent Application (OPI) No. 50041/1980 and U.S. Pat. No. 3,862,265 describe a composite material composed of a graft polyolefin and an inorganic filler which is obtained by blending an unsaturated carboxylic acid, a polyolefin, and an inorganic filler, followed by subjecting the blend to a reaction under heating and mixing in an extruder. This composite material has good affinity of the graft polyolefin for the inorganic filler but has not a sufficient flowability since it contains inorganic fibers. Therefore, a molded product prepared from this composite material has not a sufficient impact strength. Thus, composite materials having improved properties are strongly desired.

SUMMARY OF THE INVENTION

Accordingly, an object of the present invention is to provide a thermoplastic composite material which can provide a molded product having excellent mechanical properties (particularly, impact strength), a high flexial modulus a small specific gravity and a good water repllency.

Another object of the present invention is to provide a composite material having a good moldability due to its excellent flowability.

The composite material of the present invention comprises a modified polyolefin (i.e., a polyolefin modified with an unsaturated carboxylic acid), a reinforcement, and at least one polyfunctional compound selected from the group consisting of a polyfunctional epoxide, a polyfunctional amino compound, and a polyfunctional polyisocyanate compound.

DETAILED DESCRIPTION OF THE INVENTION

The modified polyolefin used in the present invention can be obtained by graft-polymerizing an unsaturated carboxylic acid onto a polyolefin and has an excellent affinity for reinforcements as compared with unmodified polyolefins.

Examples of polyolefins used for preparation of the modified polyolefin include polyethylene, polypropylene, poly(4-methylpentene-1), ethylene/vinyl acetate copolymer, ethylene/ethyl acrylate copolymer, ethylene/propylene/diene copolymer, and so forth. When polypropylene is used, a composite material having particularly various excellent characteristics can be prepared.

The modifier used for preparations of the modified polyolefin is unsaturated carboxylic acids and examples thereof include acrylic acid, methacrylic acid, itaconic acid, maleic acid, and anhydrides of these acids. The amount of these modifiers used is 0.05 to 0.8 part by weight, preferably 0.1 to 0.6 part by weight, per 100 parts by weight of the polyolefin.

A modified polyolefin prepared using a small amount of the modifier has not a sufficient affinity for the reinforcement, making it difficult to prepare a composite material having excellent properties. On the other hand, when a modified polyolefin is prepared using a large amount of the modifier, modification of the polyolefin does not proceed sufficiently, and a modified polyolefin contains a large amount of unreacted modifier. Such a product tends to deteriorate with the passage of time.

The modified polyolefin can be prepared by mixing a polyolefin, a modifier, and a catalyst in predetermined proportions and reacting the resulting mixture at 150° to 280° C. for 1 to 20 minutes. When the reaction temperature and/or the reaction time exceed(s) the abovedescribed range(s), the modified polyolefin obtained shows unfavorable coloring or unnecessary thermal decomposition.

Examples of the catalysts used for the preparation of the modified polyolefin include benzoyl peroxide, lauroyl peroxide, and ketal or dialkyl peroxides which have a decomposition temperature necessary for attaining the half life of 10 hours of at least 80° C. Specific examples of the ketal or dialkyl peroxide catalysts include 1,1-bis(t-butylperoxy)cyclohexane, n-butyl 4,4-bis(t-butylperoxy)valerate, 1,1-bis-(t-butylperoxy)-3,3,5-trimethylcyclohexane, 2,2-bis(t-butylperoxy)butane, 2,2-bis(t-butylperoxy)octane, dicumyl peroxide, t-butylcumyl peroxide, α,α'-bis(t-butylperoxyisopropyl)benzene, 2,5-dimethyl-2,5-di(t-butylperoxy)hexane, and 2,5-dimethyl-2,5-di(t-butylperoxy)hexyne-3.

When the modified polyolefin is prepared using ketal peroxides or dialkyl peroxides having a decomposition temperature necessary for attaining the half life of 10 hours of at least 80° C., it exhibits a more effective molecular weight-lowering effect as compared with the modified polyolefin prepared using other catalysts. Accordingly, the composite material of the present invention prepared using the modified polyolefin has excellent moldability. Further, in crystallization of the polymer in the process for molding of the composite material of the present invention, the modified polyolefin prepared by using the specified ketal peroxides or dialkyl peroxides and benzoyl peroxide in a weight ratio of 10/1 to 1/10, preferably 1/6 to 6/1, exhibits an effect of inhibiting the growth of spherulites and, as a result, a composite material having good characteristics (a spherulite size of 50μ or less, preferably 5 to 30μ) can be obtained.

The amount of the catalyst used is 0.03 to 3 parts by weight, preferably 0.05 to 1 part by weight, per 100 parts by weight of the polyolefin.

As a modification reaction of the polyolefins, a solution reaction process using a solvent as a reaction medium or a method in which the reaction is conducted in a heat-melting state can be employed. From the standpoint of prevention of unnecessary coloring of the modified polyolefin obtained, prevention of unnecessary lowering of the molecular weight of the polyolefin, and the choice of an appropriate reaction time, it is preferred to employ a heat-melting reaction using an extruder as a reactor.

Polyfunctional epoxy compounds used in the present invention are compounds having two or more epoxy groups in the molecule. Examples thereof include a bisphenol A type epoxy compound, a bisphenol F type epoxy compound, an aliphatic ether type epoxy compound, a novolak type epoxide, an isocyanurate type epoxide and so forth. Specific examples thereof include condensates between bisphenol A and epichlorohydrin; polyglycidyl ethers of polyols such as ethylene glycol, propylene glycol, polyethylene glycol, glycerol, neopentyl glycol, trimethylolpropane, and sorbitol; triglycidyl isocyanurate, N-methyl-N',N"-diglycidyl isocyanurate, and triglycidyl cyanurate. The molecular weight of these polyfunctional epoxides is, though not particularly limited, about 4,000 or less.

Polyfunctional amines used in the present invention are compounds having two or more amino groups in the molecule. Specific examples thereof include hexamethylenediamine, tetramethylenediamine, methaxylenediamine, diaminodiphenylmethane, diaminodiphenyl sulfone, 3,3'-diaminobenzidine, isophthalic acid hydrazide, diaminodiphenyl ether, nanomethylenediamine, and diethylenetetramine.

Polyfunctional isocyanates are compounds having two or more isocyanate groups in the molecule. Examples thereof include tetramethylene diisocyanate, toluidine diisocyanate, diphenylmethane diisocyanate, naphthalene diisocyanate, and their polyisocyanates obtained by extending them with a chain-extending agent. Of these polyfunctional compounds, polyepoxides having a cyanuric or isocyanuric ring have high reactivity toward the modified polyolefin in the process of preparing the composite material of the present invention and a molding product prepared from the composite material thus-obtained has more excellent impact strength as compared with other molded products.

Polyfunctional epoxides, polyfunctional amines, and polyfunctional isocyanates can be used alone or in combination, the amount thereof is each 0.03 to 5 wt% per the weight of the modified polyolefin but the total amount does not exceed 10 wt% per the weight of the modified polyolefin.

Molded products prepared from the composite material containing at least one of those polyfunctional amines, polyfunctional isocyanates, and polyfunctional epoxides of the present invention have an excellent strength characteristic as compared with molded products prepared from composite materials containing no those polyfunctional compounds.

Reinforcements used in the present invention are fibrous materials such as glass fibers, carbon fibers, graphite fibers, aromatic polyamide fibers, silicon carbide fibers, polysulfone type fibers, polyether ketone fibers, alumina fibers, potassium titanate fibers, asbestos fibers, boron fibers, metal fibers, and so forth. Fibers having the length of 5 mm or less, preferably 0.01 to 3 mm, are preferred.

As other reinforcements, powdery or flaky materials such as glass flakes, talc, mica, kaolin, clay, diatomaceous earth, calcium carbonate, calcium sulfate, magnesium oxide, carbon black, titanium oxide, metal powders, alumina, graphite, white carbon, wollastonite, molybdenum disulfide, and tungsten disulfide can be used. Those reinforcements are incorporated in the modified polyolefin alone or in combination thereof in an amount of 5 to 400 wt% per the weight of the modified polyolefin. If the amount of the reinforcement is too small, a sufficient reinforcing effect, high flexial modulus and high strength cannot be obtained. On the other hand, if the amount of the reinforcement is too large, moldability of the composite material is remarkable reduced and the mechanical properties of a molded product prepared from the composite material tend to deteriorate.

Other thermoplastic plastics, for example, engineering plastics such as polyamides, unmodified polyolefins, polyesters, polycarbonates, polyacetals, and polysulfones can be incorporated into the composite material of the present invention, if desired.

The composite material of the present invention is prepared by blending a modified polyolefin, at least one compound selected from the group consisting of polyfunctional epoxides, polyfunctional amines, and polyfunctional isocyanates, and a reinforcement in the predetermined proportions. This composite material can be molded into the desired molded product by an injection molding method or the like.

Moldability of the composite material of the present invention is superior to that of similar kinds of conventional composite materials. Thus, it is believed that a molded product prepared from the composite material of the present invention has sufficiently improved impact strength as compared with that prepared from similar kinds of conventional composite materials.

The present invention will now be explained in detail by reference to the following non-limiting examples. Unless otherwise indicated, all percents, parts, ratios and the like are by weight.

EXAMPLE 1

To 100 parts by weight of polypropylene powders having an inherent viscosity of 1.5 (measured in a tetralin solution at 135° C.) were added modifiers and peroxides with the amounts as shown in Table 1, and the mixture was blended in the Henschel mixer. The mixture was then fed into an extruder reactor of 30 φ and L/D=25, and modified in a mixed state under heat-melting at a reaction temperature of 230° C. for a reaction time of 7 minutes. The unreacted modifier was removed by reducing the pressure of the vent portion of the extruder, and then the reaction mixture was extruded into pellets to give modified polyolefins.

To 100 parts by weight of the resulting modified polyolefin pellets were each added prescribed amounts of reinforcements and polyfunctional compounds as shown in Table 1. The mixture was blended in a tumbler and melt mixed in an extruder, and extruded therefrom to give pellets of composite materials.

These composite materials were formed into 3 kinds of molded products, viz., plates of No. 1 dumbbell, 125×12.5×3.2 (mm), and 125×12.5×6.4 (mm) using a screw on-line type injection machine under molding conditions of a cylinder temperature of 220° C. and a mold temperature of 60° C.

The results obtained by measuring fabrication properties of the composite materials and mechanical properties of the molded products therefrom under the following conditions are shown in Table 1.

Melt Flow Index (molding flow index): ASTM-D-1238, load 2.16 kg, temperature 230° C.

Izod Impact Strength: ASTM-D-256.

Heat Distortion Temperature (hereinafter referred to as HDT): ASTM-D-648. ##EQU1##

                                      TABLE 1                                      __________________________________________________________________________                   Experiment No.                                                                 1       2      3      4      5      6     7                      __________________________________________________________________________     Composition of composite                                                       material                                                                       Polypropylene 100     100    100    100    100    100   100                    Parts by weight                                                                Peroxide                                                                       Kind          --      Benzoyl                                                                               --     Benzoyl                                                                               Benzoyl                                                                               Benzoyl                                                                              Benzoyl                                      peroxide      peroxide                                                                              peroxide                                                                              peroxide                                                                             peroxide               Parts by weight                                                                              --      0.3    --     0.3    0.3    0.3   0.3                    Modifier                                                                       Kind          --      Maleic --     Maleic Maleic Maleic                                                                               Acrylic                                      anhydride     anhydride                                                                             anhydride                                                                             anhydride                                                                            acid                   Parts by weight                                                                              --      0.3    --     0.3    0.3    0.3   0.3                    Polyfunctional compound                                                        Kind          --      --     Hexa-  Hexa-  Hexa-  --    --                                                  methylene                                                                             methylene                                                                             methylene                                                                             diamino                                                   diamine                                                                               diamine                                                                               diamine                                                                               diphenyl                                                                       ether                        Parts by weight                                                                              --      --     0.3    0.3    0.3    0.5   --                     Reinforcement                                                                  Kind          Carbon  Carbon Carbon Carbon Carbon Carbon                                                                               Carbon                               fiber   fiber  fiber  fiber  fiber  fiber fiber                  Parts by weight                                                                              25      25     25     25     25     25    25                     Mechanical property of                                                         molded product                                                                 Flexial strength                                                                             770     1,140  820    1,470  1,540  1,460 1,160                  (kg/cm.sup.2)                                                                  Flexial modulus                                                                              8.8     8.8    8.8    8.8    8.7    8.7   8.6                    (× 10.sup.4 kg/cm.sup.2)                                                 Izod impact strength                                                                         15      18     16     31     33     28    17                     (kg-cm/cm.sup.2)                                                               HDT (°C.)                                                                             145     148    145    147    143    145   148                    Ratio of improvement in                                                                      1.0     1.5    1.1    1.9    2.0    1.9   1.5                    strength (ratio)                                                               Remark        Comparative                                                                            "      "      Invention                                                                             Invention                                                                             Invention                                                                            Comparative                          Example                                   Example                __________________________________________________________________________                   Experiment No.                                                                 8      9      10     11     12     13     15                     __________________________________________________________________________     Composition of composite                                                       material                                                                       Polypropylene 100    100    100    100    100    100    100                    Parts by weight                                                                Peroxide                                                                       Kind          Benzoyl                                                                               Benzoyl                                                                               Benzoyl                                                                               Benzoyl                                                                               Benzoyl                                                                               Benzoyl                                                                               Benzoyl                              peroxide                                                                              peroxide                                                                              peroxide                                                                              peroxide                                                                              peroxide                                                                              peroxide                                                                              peroxide               Parts by weight                                                                              1.0    0.3    1.0    0.3    0.3    0.3    0.3                    Modifier                                                                       Kind          Acrylic                                                                               Acrylic                                                                               Acrylic                                                                               Maleic Maleic Maleic Maleic                               acid   acid   acid   anhydride                                                                             anhydride                                                                             anhydride                                                                             anhydride              Parts by weight                                                                              0.7    0.3    0.7    0.3    0.3    0.3    0.3                    Polyfunctional compound                                                        Kind          --     Hexa-  Hexa-  2,4-   4,4'-  Triglycidyl                                                                           Bisphenol A                                 methylene                                                                             methylene                                                                             Toluilene                                                                             Diphenyl-                                                                             isocyanurate                                                                          diglycidyl                                  diamine                                                                               diamine                                                                               diisocyanate                                                                          methane       ether                                                            diisocyanate                         Parts by weight                                                                              --     0.3    0.3    0.3    0.3    0.3    0.3                    Reinforcement                                                                  Kind          Carbon Carbon Carbon Carbon fiber                                                                          Carbon fiber                                                                          Carbon                                                                                Carbon                               fiber  fiber  fiber                       fiber                  Parts by weight                                                                              25     25     25     25     25     25     25                     Mechanical property of                                                         molded product                                                                 Flexial strength                                                                             1,230  1,460  1,570  1,530  1,550  1,580  1,460                  (kg/cm.sup.2)                                                                  Flexial modulus                                                                              8.6    8.7    8.8    8.4    8.6    8.9    8.6                    (× 10.sup.4 kg/cm.sup.2)                                                 Izod impact strength                                                                         19     29     27     34     33     32     28                     (kg-cm/cm.sup.2)                                                               HDT (°C.)                                                                             147    147    149    146    145    151    150                    Ratio of improvement in                                                                      1.6    1.9    2.0    2.0    2.0    2.1    1.9                    strength (ratio)                                                               Remark        Comparative                                                                           Invention                                                                             Invention                                                                             Invention                                                                             Invention                                                                             Invention                                                                             Invention                            Example                                                          __________________________________________________________________________                  Experiment No.                                                                 16    17     18     19      20      21     22                     __________________________________________________________________________     Composition of composite                                                       material                                                                       Polypropylene                                                                               100   100    100    100     100     100    100                    Parts by weight                                                                Peroxide                                                                       Kind         Benzoyl                                                                              Benzoyl                                                                               Benzoyl                                                                               Benzoyl Benzoyl Benzoyl                                                                               --                                  peroxide                                                                             peroxide                                                                              peroxide                                                                              peroxide                                                                               peroxide                                                                               peroxide                      Parts by weight                                                                             0.3   0.3    0.3    0.3     0.3     0.3    --                     Modifier                                                                       Kind         Maleic                                                                               Maleic Maleic Maleic  Acrylic Acrylic                                                                               --                                  anhydride                                                                            anhydride                                                                             anhydride                                                                             anhydride                                                                              acid    acid                          Parts by weight                                                                             0.3   0.3    0.3    0.3     0.3     0.3    --                     Polyfunctional compound                                                        Kind         Neopentyl-                                                                           --     Triglycidyl                                                                           Hexamethylene                                                                          Hexamethylene                                                                          Triglycidyl                                                                           --                                  glycol di-   isocyanurate                                                                          diamine diamine isocyanurate                               glycidyl                                                                       ether                                                             Parts by weight                                                                             0.3   --     0.3    0.3     0.3     0.3    --                     Reinforcement                                                                  Kind         Carbon                                                                               Glass  Glass fiber                                                                           Glass fiber                                                                            Glass fiber                                                                            Carbon Talc                                fiber fiber                         fiber                         Parts by weight                                                                             25    25     25     25      25      25     25                     Mechanical property of                                                         molded product                                                                 Flexial strength                                                                            1,500 1,080  1,330  1,280   1,250   1,600  430                    (kg/cm.sup.2 )                                                                 Flexial modulus                                                                             8.7   5.3    5.5    5.4     5.3     8.5    4.3                    (× 10.sup.4 kg/cm.sup.2)                                                 Izod impact strength                                                                        30    20     25     27      28      30     10                     (kg-cm/cm.sup.2)                                                               HDT (°C.)                                                                            151   145    144    145     148     149    80                     Ratio of improvement in                                                                     1.9   1.2    1.5    1.5     1.4     2.1    1.0                    strength (ratio)                                                               Remark       Invention                                                                            Comparative                                                                           Invention                                                                             Invention                                                                              Invention                                                                              Invention                                                                             Comparative                               Example                              Example                __________________________________________________________________________                   Experiment No.                                                                 23      24          25     26     27      28                     __________________________________________________________________________     Composition of composite                                                       material                                                                       Polypropylene 100     100         100    100    100     100                    Parts by weight                                                                Peroxide                                                                       Kind          Benzoyl Benzoyl peroxide                                                                           Benzoyl                                                                               Benzoyl                                                                               Benzoyl Benzoyl                              peroxide            peroxide                                                                              peroxide                                                                              peroxide                                                                               peroxide               Parts by weight                                                                              0.3     0.3         0.3    0.3    0.3     0.7                    Modifier                                                                       Kind          Maleic  Maleic anhydride                                                                           Maleic Maleic Maleic  Maleic                               anhydride           anhydride                                                                             anhydride                                                                             anhydride                                                                              anhydride              Parts by weight                                                                              0.3     0.3         0.3    0.3    0.3     0.7                    Polyfunctional compound                                                        Kind          --      4,4-Diphenylmethylene                                                                      Triglycidyl                                                                           Triglycidyl                                                                           Triglycidyl                                                                            Triglycidyl                                  diisocyanate                                                                               isocyanurate                                                                          isocyanurate                                                                          isocyanurate                                                                           isocyanurate           Parts by weight                                                                              --      0.5         0.3    0.3    0.3     0.3                    Reinforcement                                                                  Kind          Talc    Talc        Talc   Glass fiber                                                                           Talc/carbon                                                                            Carbon fiber                                                           fiber = 1/1                    Parts by weight                                                                              25      25          25     25     50      25                     Mechanical property of                                                         molded product                                                                 Flexial strength                                                                             500     560         540    1,320  1,530   1,640                  (kg/cm.sup.2)                                                                  Flexial modulus                                                                              4.3     4.3         4.5    5.4    10.1    8.2                    (× 10.sup.4 kg/cm.sup.2)                                                 Izod impact strength                                                                         10      19          17     27     29      32                     (kg-cm/cm.sup.2)                                                               HDT (°C.)                                                                             80      82          80     148    149     149                    Ratio of improvement in                                                                      1.0     1.3         1.3    1.5    2.0     2.1                    strength (ratio)                                                               Remark        Comparative                                                                            Invention   Invention                                                                             Invention                                                                             Invention                                                                              Invention                            Example                                                          __________________________________________________________________________                   Experiment No.                                                                 29      30      31       32      33      34                      __________________________________________________________________________     Composition of composite                                                       material                                                                       Polypropylene 100     100     100      100     100     100                     Parts by weight                                                                Peroxide                                                                       Kind          1,1-Bis(t-                                                                             2,5-Dimethyl-                                                                          Benzoyl  *1      *2      *2                                    butylperoxy)-                                                                          2,5-di(t-                                                                              peroxide                                                       3,3,5-  butylperoxy)-                                                          trimethyl-                                                                             hexyne-3                                                               cyclohexane                                                      Parts by weight                                                                              0.2     0.2     0.       0.2     0.2     0.2                     Modifier                                                                       Kind          Maleic  Maleic  Maleic   Maleic  Maleic  Maleic                                anhydride                                                                              anhydride                                                                              anhydride                                                                               anhydride                                                                              anhydride                                                                              anhydride               Parts by weight                                                                              0.3     0.3     0.3      0.3     0.3     0.3                     Polyfunctional compound                                                        Kind          Triglycidyl                                                                            Triglycidyl                                                                            Triglycidyl                                                                             Triglycidyl                                                                            Triglycidyl                                                                            Triglycidyl                           isocyanurate                                                                           isocyanurate                                                                           isocyanurate                                                                            isocyanurate                                                                           isocyanurate                                                                           isocyanurate            Parts by weight                                                                              0.3     0.3     0.3      0.3     0.3     0.3                     Reinforcement                                                                  Kind          Carbon fiber                                                                           Carbon fiber                                                                           Carbon fiber                                                                            Carbon fiber                                                                           Carbon fiber                                                                           Carbon fiber            Parts by weight                                                                              25      25      25       25      25      25                      Mechanical property of                                                         molded product                                                                 Flexial strength                                                                             1,480   1,450   770      1,500   1,560   1,470                   (kg/cm.sup.2)                                                                  Flexial modulus                                                                              8.7     8.7     8.4      8.6     8.7     8.6                     (× 10.sup.4 kg/cm.sup.2)                                                 Izod impact strength                                                                         29      20      11       35      33      17                      (kg-cm/cm.sup.2)                                                               HDT (°C.)                                                                             144     146     141      148     149     145                     Ratio of improvement in                                                                      1.9     1.4     1.0      1.9     2.0     1.9                     strength (ratio)                                                               Remark        Invention                                                                              Invention                                                                              Comparative                                                                             Invention                                                                              Invention                                                                              Invention                                             Example                                          MFI (g/10 min)        39.9    6.1                                              Spherical size (μ)                                                                        100     100     100      10      10      100                     Moldability into flat                                                                        Better  Best    Bad      Better  Better  Better                  plate 1 mm thick                                                               __________________________________________________________________________                   Experiment No.                                                                 35      36       37     38      39      40                       __________________________________________________________________________     Composition of composite                                                       material                                                                       Polypropylene 100     100      100    100     100     100                      Parts by weight                                                                Peroxide                                                                       Kind          --      Benzoyl  Benzoyl                                                                               Benzoyl *1      *1                                             peroxide peroxide                                                                              peroxide                                 Parts by weight                                                                              --      0.2      0.2    0.2     0.2     0.2                      Modifier                                                                       Kind          --      Maleic   Maleic Maleic  Maleic  Maleic                                         anhydride                                                                               anhydride                                                                             anhydride                                                                              anhydride                                                                              anhydride                Parts by weight                                                                              --      0.3      0.3    0.3     0.3     0.3                      Polyfunctional compound                                                        Kind          Triglycidyl                                                                            Triglycidyl                                                                             Hexa-  Bisphenol A                                                                            Triglycidyl                                                                            Hexamethylene                          isocyanurate                                                                           isocyanurate                                                                            methylene                                                                             diglycidyl                                                                             isocyanurate                                                                           diamine                                                 diamine                                                                               ether                                    Parts by weight                                                                              0.3     0.6      0.6    0.6     0.6     0.6                      Reinforcement                                                                  Kind          Carbon fiber                                                                           Carbon fiber                                                                            Carbon Carbon  Carbon fiber                                                                           Carbon fiber                                            fiber  fiber                                    Parts by weight                                                                              25      25       25     25      25      25                       Mechanical property of                                                         molded product                                                                 Flexial strength                                                                             750     1,750    1,520  1,510   1,700   1,480                    (kg/cm.sup.2)                                                                  Flexial modulus                                                                              8.3     8.6      8.5    8.7     8.7     8.6                      (× 10.sup.4 kg/cm.sup.2)                                                 Izod impact strength                                                                         13      40       33     30      38      30                       (kg-cm/cm.sup.2)                                                               HDT (°C.)                                                                             141     145      144    146     146     145                      Ratio of improvement in                                                                      1.0     2.3      2.0    2.0     2.2     1.9                      strength (ratio)                                                               Remark        Comparative                                                                            Invention                                                                               Invention                                                                             Invention                                                                              Invention                                                                              Invention                              Example                                                          MFI (g/10 min)                                                                               5.6                                                              Spherical size (μ)                                                                        100     10       10     10      10      10                       Moldability into flat                                                                        Bad     Good     Good   Good    Best    Best                     plate 1 mm thick                                                               __________________________________________________________________________                   Experiment No.                                                                 41      42      43      44      45       46                      __________________________________________________________________________     Composition of composite                                                       material                                                                       Polypropylene 100     100     100     100     100      100                     Parts by weight                                                                Peroxide                                                                       Kind          *1      --      Benzoyl --      Benzoyl  Benzoyl                                               peroxide        peroxide peroxide                Parts by weight                                                                              0.2     --      0.3     --      0.3      0.3                     Modifier                                                                       Kind          Maleic  --      Maleic  --      Maleic   Maleic                                anhydride       anhydride       anhydride                                                                               anhydride               Parts by weight                                                                              0.3     --      0.3     --      0.3      0.3                     Polyfunctional compound                                                        Kind          Bisphenol A                                                                            --      --      Triglycidyl                                                                            Triglycidyl                                                                             Triglycidyl                           diglycidyl              isocyanurate                                                                           isocyanurate                                                                            isocyanurate                          ether                                                            Parts by weight                                                                              0.6     --      --      0.3     0.3      3.0                     Reinforcement                                                                  Kind          Carbon  Carbon  Carbon  Carbon  Carbon   Carbon                                fiber   fiber   fiber   fiber   fiber    fiber                   Parts by weight                                                                              25      100     100     100     100      100                     Mechanical property of                                                         molded product                                                                 Flexial strength                                                                             1,470   990     1,450   950     1,950    2,110                   (kg/cm.sup.2)                                                                  Flexial modulus                                                                              8.6     21.5    22.0    21.8    22.2     27.3                    (× 10.sup.4 kg/cm.sup.2)                                                 Izod impact strength                                                                         29      10      17      11      28       25                      (kg-cm/cm.sup.2)                                                               HDT (°C.)                                                                             146     149     148     148     148      149                     Ratio of improvement in                                                                      1.9     1.0     1.5     1.0     2.0      --                      strength (ratio)                                                               Remark        Invention                                                                              Comparative                                                                            "       "       Invention                                                                               Invention                                     Example                                                  MFI (g/10 min)                                                                               10      3       6       3       5                                Spherical size (μ)                                                                        10                                                               Moldability into flat                                                                        Best                                                             plate 1 mm thick                                                               __________________________________________________________________________                   Experiment No.                                                                 47     48      49      50       51       52                      __________________________________________________________________________     Composition of composite                                                       material                                                                       Polypropylene 100    100     100     100      100     100                      Parts by weight                                                                Peroxide                                                                       Kind          Benzoyl                                                                               Benzoyl Benzoyl --       --      --                                     peroxide                                                                              peroxide                                                                               peroxide                                          Parts by weight                                                                              0.3    0.3     0.3     --       --      --                       Modifier                                                                       Kind          Acrylic                                                                               Maleic  Maleic  --       Maleic  --                                     acid   anhydride                                                                              anhydride        anhydride                        Parts by weight                                                                              0.3    0.3     0.3     --       0.3     --                       Polyfunctional compound                                                        Kind          Triglycidyl                                                                           Hexameth-                                                                              4,4'-diphenyl                                                                          --       --      Triglycidyl                            isocyanu-                                                                             ylene   methane                  isocyanurate                           rate   diamine diisocya-                                                                      nate                                              Parts by weight                                                                              0.3    0.3     0.3     --       --      0.3                      Reinforcement                                                                  Kind          Carbon Carbon  Carbon  Glass    Glass   Glass fiber                            fiber  fiber   fiber   fiber    fiber                            Parts by weight                                                                              100    100     100     100      100     100                      Mechanical property of                                                         molded product                                                                 Flexial strength                                                                             1,900  1,870   1,810   1,000    1,240   970                      (kg/cm.sup.2)                                                                  Flexial modulus                                                                              22.0   21.6    22.3    15.0     15.2    15.1                     (× 10.sup.4 kg/cm.sup.2)                                                 Izod impact strength                                                                         27     26      28      12       19      13                       (kg-cm/cm.sup.2)                                                               HDT (°C.)                                                                             149    148     147     148      149     148                      Ratio of improvement in                                                                      1.9    1.9     1.8     1.0      1.2     1.0                      Remark        Invention                                                                             Invention                                                                              Invention                                                                              Comparative                                                                             Comparative                                                                            Comparative                                                   Example  Example Example                  __________________________________________________________________________                   Experiment No.                                                                 53      54      55      56       57      58                      __________________________________________________________________________     Composition of composite                                                       material                                                                       Polypropylene 100     100     100     100      100     100                     Parts by weight                                                                Peroxide                                                                       Kind          Benzoyl 1,1-Bis(t-                                                                             *1      --       Benzoyl Benzoyl                               peroxide                                                                               butylperoxy)-            peroxide                                                                               peroxide                                      3,3,5-                                                                         trimethyl-                                                                     cyclohexane                                              Parts by weight                                                                              0.3     0.3     0.3     --       0.3     0.3                     Modifier                                                                       Kind          Maleic  Maleic  Maleic  --       Maleic  Maleic                                anhydride                                                                              anhydride                                                                              anhydride        anhydride                                                                              anhydride               Parts by weight                                                                              0.3     0.3     0.3     --       0.3     0.3                     Polyfunctional compound                                                        Kind          Triglycidyl                                                                            Triglycidyl                                                                            Triglycidyl                                                                            --       --      Triglycidyl                           isocyanurate                                                                           isocyanurate                                                                           isocyanurate             isocyanurate            Parts by weight                                                                              0.3     0.3     0.3     --       --      0.3                     Reinforcement                                                                  Kind          Glass fiber                                                                            Carbon fiber                                                                           Carbon fiber                                                                           Calcium  Calcium Calcium                                                       carbonate                                                                               carbonate                                                                              carbonate               Parts by weight                                                                              100     100     100     100      100     100                     Mechanical property of                                                         molded product                                                                 Flexial strength                                                                             1,590   1,850   1,920   390      510     600                     (kg/cm.sup.2)                                                                  Flexial modulus                                                                              15.0    22.0    22.1    5.4      5.4     5.3                     (× 10.sup.4 kg/cm.sup.2)                                                 Izod impact strength                                                                         24      22      27      8        9       16                      (kg-cm/cm.sup.2)                                                               HDT (°C.)                                                                             149     148     149     80       80      80                      Ratio of improvement in                                                                      1.6     1.9     1.9     1.0      1.3     1.5                     strength (ratio)                                                               Remark        Invention                                                                              Invention                                                                              Invention                                                                              Comparative                                                                             Comparative                                                                            Invention                                                     Example  Example                         MFI (g/10 min)        14      12                                               __________________________________________________________________________      Notes                                                                          *1: A mixture of benzoyl peroxide and                                          1,1bis(t-butylperoxy)-3,3,5-trimethylcyclohexane (1:1)                         *2: A mixture of benzoyl peroxide and                                          2,5dimethyl-2,5-di(t-butylperoxy)hexyne-3 (1:1)                          

EXAMPLE 2

To 100 parts by weight of polypropylene powders having an inherent viscosity of 2.0 (measured in a tetralin solution of 135° C.) were each added peroxides as shown in Table 2 and 0.3 part of maleic anhydride as a modifier, and the mixture was blended uniformly in the Henschel mixer. The mixture was then subjected to a heat-melting reaction under conditions of a reaction temperature of 250° C. and a reaction time period of 7 minutes.

The results obtained by measuring the inherent viscosity of modified polypropylenes thus-obtained are shown in Table 2 below.

                  TABLE 2                                                          ______________________________________                                                      Inherent Viscosity                                                             Amount of Peroxide Added (parts)                                  Peroxide       0      0.05   0.1  0.3  0.4  0.8                                ______________________________________                                         Benzoyl peroxide                                                                              1.75   1.73   1.70 1.62 1.6  1.56                               1,1-Bis(t-butylperoxy)-                                                                       1.75   1.45   1.3  1.00 0.95 --                                 3,3,5-trimethyl cyclo-                                                         hexane                                                                         Dicumyl peroxide                                                                              1.75   1.08   1.32 1.08 0.98 --                                 Benzoyl peroxide/1,1-                                                                         1.75   --     1.31 1.09 --   --                                 Bis(t-butylperoxy)-3,3,5-                                                      trimethyl cyclohexane (1:1                                                     weight ratio mixture)                                                          ______________________________________                                    

While the invention has been described in detail and with reference to specific embodiments thereof, it will be apparent to one skilled in the art that various changes and modifications can be made therein without departing from the spirit and scope thereof. 

What is claimed is:
 1. A polyolefin resin composition comprising:(a) a polyolefin selected from the group consisting of polyethylene, polypropylene, poly(4-methylpentene-1), ethylene/vinyl acetate copolymer, ethylene/ethylacrylate copolymer, and ethylene/propylene/diene copolymer modified with from 0.05 to 0.8 parts by weight per 100 parts by weight of the polyolefin, of a grafted unsaturated carboxylic acid; (b) no more than 10 weight %, based on the weight of said modified polyolefin, of a polyfunctional epoxide, polyfunctional amine, polyfunctional isocyanate or mixtures thereof with the proviso that the amount of any given polyfunctional agent is within the range of 0.03 to 5 wt. %; and (c) from 5 to 400 wt. % of a reinforcing material, based on the weight of the modified polyolefin, of (i) a fibrous material selected from the group of glass fibers, carbon fibers, graphite fibers, aromatic polyamide fibers, silicon carbide fibers, polysulfone fibers, polyether ketone fibers, alumina fibers, potassium titanate fibers, asbestos fibers, boron fibers or metal fibers; or (ii) powdery or flaky materials selected from the group consisting of glass flakes, talc, mica, kaolin, clay, diatomaceous earth, calcium carbonate, calcium sulfate, magnesium oxide, carbon black, titanium oxide, powdered metal, alumina, graphite, white carbon, wollastonite, molybdenum disulfide and tungsten disulfide.
 2. The composition of claim 1, wherein the modified polyolefin is prepared by reacting a polyolefin and said unsaturated carboxylic acid in the presence of at least one catalyst selected from the group consisting of ketal peroxides and dialkyl peroxides which have a decomposition temperature necessary for attaining the half life of 10 hours of at least 80° C.
 3. The composition of claim 1, wherein the modified polyolefin is prepared by reacting a polyolefin and said unsaturated carboxylic acid in the presence of a mixed catalyst system comprising at least one member selected from the group consisting of ketal peroxides and dialkyl peroxides which have a decomposition temperature necessary for obtaining the half life of 10 hours of at least 80° C., and benzoyl peroxide.
 4. The polyolefin resin composition of claim 3, wherein the weight ratio of said at least one member selected from the group consisting of ketal peroxides and dialkyl peroxides to benzoyl peroxide in the mixed catalyst system is 1/10 to 1/1.
 5. The polyolefin resin composition of claim 1, wherein the modified polyolefin is prepared by heat-melting the unsaturated carboxylic acid, the polyolefin, and the polyfunctional compound in the presence of a peroxide type catalyst.
 6. The composition of claim 5, wherein the modified polyolefin is prepared by extruding the reactants which form the same from an extruder type reactor.
 7. The polyolefin resin composition of claim 2, wherein the ketal or dialkyl peroxide catalyst is at least one member selected from the group consisting of 1,1-bis(t-butylperoxy)-3,3,5-trimethylcyclohexane, 1,1-bis(t-butylperoxy)cyclohexane, n-butyl 4,4-bis(t-butylperoxy)valerate, 2,2-bis(t-butylperoxy)butane, 2,2-bis(t-butylperoxy)octane, di-t-butyl peroxide, t-butylcumyl peroxide, dicumyl peroxide ˜,˜'-bis(t-butylperoxyisopropyl)benzene, and 2,5-dimethyl-2,5-di(t-butylperoxy)hexyne-3.
 8. The composition of claim 3, wherein the modified polyolefin is in the form of spherulites of a size of 50μ or less.
 9. The composition of claim 1, wherein the polyfunctional compound is a polyepoxide having an isocyanurate or cyanurate ring.
 10. The composition of claim 1, wherein the improvement ratio of the strength of a molded product prepared from a composition consisting of the modified polyolefin and said reinforcing material to that of a molded product prepared from a polyolefin resin composition consisting of an unmodified polyolefin and said reinforcing material is at least 1.5.
 11. The composition of claim 1, wherein said polyfunctional epoxide is a bisphenol A epoxy compound, a bisphenol F epoxy compound, an aliphatic ether epoxy compound, a novolak epoxide or an isocyanurate epoxide.
 12. The composition of claim 1, wherein said polyfunctional amine is hexamethylene diamine, tetramethylene diamine, methaxylene diamine, diamino diphenylmethane, diaminodiphenyl sulfone, 3,3'-diaminobenzidine, isophthalic acid hydrazide, diamino diphenyl ether, nanomethylenediamine or diethylenetetramine.
 13. The composition of claim 1, wherein said polyfunctional isocyanate is tetramethylene diisocyanate, toluidine diisocyanate, diphenylmethane diisocyanate, naphthalene diisocyanate or a polyisocyanate obtained by extending a diisocyanate compound with a chain extending agent.
 14. A polyolefin resin composition comprising:(a) a polyolefin selected from the group consisting of polyethylene, polypropylene, poly(4-methylpentene-1), ethylene/vinyl acetate copolymer, ethylene/ethylacrylate copolymer, and ethylene/propylene/diene copolymer modified with from 0.05 to 0.8 parts by weight per 100 parts by weight of the polyolefin, of a grafted unsaturated carboxylic acid; (b) no more than 10 weight %, based on the weight of said modified polyolefin, of a polyfunctional epoxide, polyfunctional amine, polyfunctional isocyanate or mixtures thereof with the proviso that the amount of any given polyfunctional agent is within the range of 0.03 to 5 wt. %; and (c) from 5 to 400 wt. % of a reinforcing material, based on the weight of the modified polyolefin, of (i) an inorganic fiber or (ii) at least one member selected from the group consisting of glass flakes, talc, calcium carbonate, magnesium oxide, clay, mica and carbon black or (iii) an aromatic polyamide fiber.
 15. The composition of claim 14, wherein the reinforcing material is carbon fiber. 